1. Field of the Invention
This invention relates to brake light switches for engine brakes and particularly to break light switches for engine brakes that utilize relays to operate the system.
2. Description of the Prior Art
Large trucks have an engine braking system to help stop the truck. The engine brakes are well known in the art. While effective, they have one flaw. Presently, there in no indication that a truck is using its engine brake to following vehicles. When standard brakes are employed, a switch engages a set of brake lights whenever the brake pedal is engaged. No such system is used when the engine brakes are used. Thus, following vehicles are often unaware that a large truck is braking, which creates a safety hazard.
Two patents that attempt to solve this problem are U.S. Pat. No. 5,426,418 and U.S. Pat. No. 6,137,401. In both of these patents, the brake lights are controlled by the engine brake switch. Thus, when the engine brake master switch is employed, the brake lights are energized. Note also, that both circuits are limited to positive switch circuits only. They will not work on the common negative switch circuits being used today. Finally, because they are both activated by the engine brake switch, they are not necessarily in sync with the actual braking. The engine brakes use up to three solenoids to actually initiate the braking. If the solenoids do not receive power, the brake lights will be illuminated anyway.